To prevent or at least cut down on spam? Pretty much the entire reason captcha systems were created in the first place and an entirely legitimate reason?
In addition to spam, preventing bots from buying up all the GPUs and PS5s in the recent past would have been nice.
Though in the end you're the one clicking busses and bikes and bridges and busses again and when you're through that charade, everything is gone anyway because the bots were faster/better at that..